ENDOSCOPIC ANTERIOR CERVICAL MICROFORAMINOTOMY

DR. JHO'S TECHNIQUE WITH DESTANDAU'S ENDOSPINE

Cervical radiculopathy caused by degenerative cervical spine disorders is a common medical
problem. Compressive radiculopathy is a result of several factors, posterolateral disc herniation,
uncodiscarthrosis, or facet hypertrophy. Until now two major surgical techniques have been favored,
the anterior and posterior approaches. The anterior technique is a standard technique, but the
lateral osteophytes are difficult to resect. Fusion is usually necessary. Posterior approach is
less invasive, effective, and not associated with need for fusion. Posterior approach has
disadvantage of requiring the manipulation of the cervical nerve root to access anteriorly located
offending processes.

PRINCIPLES OF THE ANTEROLATERAL APPROACH

The concept is based on the fact that anterolateral compression of the cervical nerve root,
caused by a posterolateral disc herniation or uncodiscarthrosis causing foraminal stenosis,
needs to be treated by an anterolateral approach because it gives direct access to the
offending pathology. This approach was first described by Verbiest 40 years ago.

ADVANTAGES OF THE ANTEROLATERAL APPROACH

Disc excision is limited to its lateral part, facet jt. is not damaged.

Nerve root decompression is achieved without much manipulation under vision.

Vertebral artery is under vision.

DISADVANTAGES OF THE ANTEROLATERAL APPROACH

Bilateral radiculopathies require bilateral approach.

Technique requires steep learning curve.

SURGICAL TECHNIQUE

The pt. is placed in supine position. Skin incision is marked on the symptomatic side after
localization and two third incision is medial to border of sternocleidomastoid and one third is
lateral to it. After dissection the trachea and oesophagus retracted medially and carotid sheath
laterally. The outer tube of Endospine helps in retracting the important structures with less trauma.
Then the pathological disc space confirmed with fluroscopy again. Medial portion of the longus
colli muscle excised to expose the medial parts of the transverse processes of the upper and lower
vertebrae.

In between the two transverse processes the uncovertebral joint can be seen.

MICRODISECTOMY AND MICROFORAMINOTOMY

The uncovertebral jt. is removed with a high speed microsurgical drill 3mm tip to achieve
anterior microforaminotomy. With drill the end plates and cortical bones of the uncovertebral
junction of lower vertebra and lower corner of upper vertebra are removed. As drilling advances
posteriorly, the direction of the drill is gently inclined medially. When the posterior
longitudinal ligament is exposed, a piece of thin cortical bone is left behind attached
laterally to the periosteal and ligamentous tissue covering the VA (Vertebral Artery).
This lateral remnant of the uncinate process is dissected from ligamentous tissue and
fractured at the base of uncinate process. It is further disscected from the surrounding
soft tissue and then removed, which exposes the VA in between the two transverse processes and
can be appreciated by its pulsations. The size of the hole made by the drilling at the
uncovertebral joint is usually approximately 5-6mm wide transversely and 7-8 mm vertically.
If there is no ruptured disc fragment behind the posterior longitudinal ligament, this will
be the end of the nerve root decompression.

If the nerve root is compressed by a subligamentous or an extruded posterolateral disc
herniation, the blunt nerve hook is used to remove the disc fragment. The posterior ligament
is incised and removed with 1 mm. Kerrison punch. Now we can see the anterior duramater and
nerve root emerging from the dura. Any extruded disc herniation is mobilized and pulled out,
releasing the nerve root compression. After the completion of the procedure, the cervical root
is fully exposed from its dural origin to its posterior crossing with the VA.

This anterior endoscopc microforaminotomy preserves the motion unit anatomically as well
as functionally.